Electric tube-welding machine



Dec. 13, 1927.

I 1,652,481 ca. v. JOHNSTON ELECTRIC TUBE WELDING MACHINE F iled Nov-19,1923 s Sheets-Sheet 1 v (/676607! Gzzsfa U6 7470/7275107a Dec. 13, 1927.1,652,481

I G. v. JOHNSTON ELECTRIC TUBE WELDING MACHINE Filed Nov119, I923 3Sheets-Sheet 2 Dec. l3, 1927.

1,652,481 G. v. JOHNSTON ELECTRIC TUBE WELDING MACHINE Filed Nov. 19,1923 s Sheets-$heet 3 Patented Dec. 13, 1927.

UNITED STATES PATENT OFFICE.

GUSTAVE V.

JOHNSTON, O]? CHICAGO, ILLINOIS, ASSIGNOR TO STEEL AND TUBES, IN-

CORPORATED, OF CLEVELAND, OHIO, A CORPORATION OF OHIO.

ELECTRIC TUBE-WELDING MACHINE.

Application filed November 19', 1923. Serial No. 675,453.

" speed operation under most eflicient operating conditions; to providean organization of roller-electrodes and cooperating supporting rollermeans to constitute a welding throat for handling the moving tube-stockmost eitectively under requisite pressure and with .greatest accuracy inbutt-to-butt presentation of the edges of the seam-cleft; to co-relatethe roller electrode to the transformer which supplies welding currentthereto, for most efiective cooperation; and to provideelectrode-contacting brush-means for establishing most simple, reliableand efficient lowresistance connection between the transformerssecondary terminal and said electrode. Other and further objects of myinvention are to provide atube-welder that, throughout, is simple,rugged, inexpensive in manufacture, easily maintained and facilelyoperated.

To these ends my invention consists in the combinations of parts andfeatures of construction hereinafter described and claimed.

In the drawings wherein I have shown a single embodiment of myinvention, for purposes of full disclosure of one desirable form.thereof, Figure 1 is a transverse vertical section, with parts inelevation, through the welding machine at its welding throat; Fig. 2 isa side elevation, with the right hand electrode removed and with partsin section; and Fig. 3 is an inverted plan view of the brusharrangement, with parts broken away. I

In the drawings, 10 indicates the main frame of the machine. On it aremounted the parts which provide the welding throat 11, shown ascomprising two opposed peripherally grooved roller electrodes 12, 12 and:ooperating grooved pressure-roller means 13, and on it is also mountedthe electrical transformer 14 for supplying current of low voltage andlarge amperage to the electrodes through the interveningbrush-connections straddling the seam-cleft, and the seam will beresistance-welded by the flow of alternatmg current impulses across theseam-cleft, between the electrodes, while the stock is under pressure inits passage through the throat. The longitudinal movement of thetube-stock may be caused in any suitable way. Usually it is desirable toweld the tubing continuously in long runs, as the open-seamed stockleaves the forming machine, and therefore, diagrammatically, I haveillustrated at 16 and 16 certain power-driven means, respectivelytypified as the terminal rollers of the tube-forming machine, andcertain tube strengthening rollers, either or both of which may be usedfor impelling the stock through 1 the welding throat. Thus in theparticular embodiment shown the throat-rollers will be frictionallyrotated by contact with'the tubing, rather than themselves beingpowerdriven, as they may be if desired.

In the general organization of the machineI arrange the rollerelectrodes 12, 12 on upwardly extending axes, preferably convergentlyinclined somewhat to the vertical, and dispose the transformer 14: invertical register with these electrodes so that the secondary 17 of thetransformer (which preferably is a single-turn, slotted comb or coil inthe form of an integral copper casting) may be provided withterminalportions 18, 18, in vertical line with and preferably substanti.lly parallel with, the confronting faces of tne roller electrodesbetween the axes of rotation of said electrodes. To establish electricalconnection between each electrode and the respective under-side of thesecondary terminal that is illustrated as directly above the electrode,provide laminated contact brushes of copper, the brush-strips 19 beingarranged in the slots of a brush-holder 20 in arrangement to makeend-contact of the brush-strips with both the roller electrode and thetransformer terminal, and the transformer being capacitated for verticaladjustment to vary the tension placed upon the brushes and take up wear.

In the specific construction shown each terminal part 18 of thetransformer has its under face dressed off to an inclined planecorresponding with the plane of inclination of the upper surface of thesubjacent electrode 12, and carries a brush-holder 20 shaped ininverted-plan on a curve correspondin with the vertical projection of aelectrode.

margma ortion of the face of the electrode. This brus -holder ismarginally slotted as at 21 to receive the brushes 19, each of which ispreferably of inverted l.'-shape so that its upper leg may overlie aportion of the brush-holder and its lon er leg may depend below thebrush-holder or contact with the The slots 21 are cut at such an angleas properly to incline the brushes so that they lead to the surface ofthe electrodes at an acute angle in the direction of intended rotationof the e 'ectrodes. Adjustable bolts 22 secure the brush-holder to thesecondary terminal, forcing the upper ends of the brushes into contactwith said terminal-under re uisite pressure.

t will thus be seen that the electrical connections are establishedwithout recourse to joints between large flatsurfaces which, even whenmost carefully and expensively made, are nevertheless susceptible tosome burning and deterioration and occasion a substantial voltage dropin the current supplied to the electrode. The connections aforded asherein shown, establish such short, direct connection through such a lare number of thin end-presented brushaminae, as insures high efliciencyin the conduction of current to the electrodes. Inmounting thetransformer 14 for vertical adjustment, I provide on the. housing 23 ofthe transformer suitable brackets 24 slidably embracing the verticalframe-posts 25 that rise from the main frame 10. The posts arepreferably shouldered to receive a cross-frame structure 26, and throughit extends a suspension bolt 27 non-rotatably engaging and carrying thecover 23 of the transforms]? housing, said bolt making threadedengagement with the adjusting nut eral portions may come 28 which bearson the cross frame 26 and is preferably provided with easily accessiblemeans to facilitate. its rotation. Thus the nut is preferably formedperipherally as a worm wheel 28 engaged by a worm 29, suitably carriedby the cross-"frame 26, the wormshaft 30 being equipped'with aconveniently accessible hand-wheel 31. Of course the worm gearing actsas an adjustment-lock in addition to enabling nut adjustment to be mosteasily effected. A liftin ring 33, connected to the said bolt 27, enales the entire strugture to be raised, as by a crane, when desire Whilethe brush-contact arrangement, and disposition of the transformer, asdescribed, may beem-ployed with the electrodes in any position betweenhorizontality and a considerable angle from the horizontal, I refer toarrange the electrodes at an angle su stantially as shown, such thattheir upper periphuite close together ad acent to the seam-ole and yetthe peripheries may be, symmetrically and rather shallowly grooved.Thus, as shown, the electrodeooves 12 are rather shallow, for minimizinginequality of wear, lie between symmetrical beveled edge-portions 12facilitating easy dressing of the entire periphery, and apply theiropposing pressures to the tube in direction tendin to force the buttededges of the seam together in very accurate register, all whileproviding a substantial arc of contact adequate for carrying heavycurrent: The cooperating supporting-roller 13 is preferably of unitaryconstruction symmetrically grooved and nearly completing the enclosureof'the tube stock by its cooperation. with the electrodes. It may beofeither conductin or non-conducting material and prefera ly is mountedin ball bearings in a sub-frame 36 whichzis longitudinally adjustable ontable 36 of the main frame 10. The adjusting screws 37 taking throughlugs 31' on the table 36' and abutting against the sub-frame, determineits longitudinal position while the vertical bolts 38 extend throughlongitudinal slots in the sub-frame to permit of the adjustment.

Theroller electrodes are preferably transversely adjustable in the planeof their presentation to the work, to compensate for wear or dressingand to secure just the requisite pressure, and each electrode preferablyhas its contact-disc readily removable from its bearing-shaft. Thus eachelectrode 12. is shown as insulatedly secured by bolts 40 to ashaft-head 41 of shaft 42, which is 100 mounted in ha bearings 43 in aslide carriage 44, this carriage being slidable, in parallelism with theplane of the electrode disc, in a sub-frame 4;) which is itselftransversely adjustable. An adjusting screw by the sub-frame and oerated by hand wheel 47 engages a threa ed portion 48 of the carriagefor effecting requisite adjust ment. The sub-frame is transverselyslotted to receive the bolts 49 which connect 110' it to the main table36', and for its lateral adjustment set screws 50 are rovided in itsside edgesto bear respective subsframe 36 for the supporting roller andagainst side-flanges 51 formed on the table 115 While I have hereindescribed in some de tail a particular embodiment of my invention forpurposes of full disclosure of one advantageous form thereof, it willbeunder 12o stood by those skilled in the art changes may be made in theem my invention without departure. from v its that many spirit andwithin the scope of the appended 125 claims.

- I claim:

1. In an electric welding machine, the combination of a transformerhavin vertical secondary terminals presentin fl at contact-surfaces attheir ends; a wel ng-throat 46 carried y against the odiment ofstructure including two opposed roller-electrodes rotatable aboutupwardly-extending axes and each presenting, transversely to its axis,an annular side-surface for traveling contact, the contact-portionthereof-being in vertical register with and confronting the endcontact-surface of a corresponding one of said secondary terminals;upwardly-extending contact brushes interposed endwise between, anddirectly establishing low resistance electrical connection between, theconfronting surfaces of said secondary terminals and respectiveelectrodes, said brushes making contact at their end-surfaces only withsaid terminals and electrodes, and a removable brush holder retainingsaid brushes in operative position, said brushes being removablypositioned in said holder.

2-. In an electric welding machine, the combination of a welding-throatstructure including two opposed electrodes rotatable about upwardlyextending axes, a transformer directly above said electrodes and havingdepending secondary terminals respectively located above said electrodesand between the axes of the latter, contact brushes interposed between,and making end-contact with, respectively a marginal portion of eachelectrode and the under side of the corresponding secondary terminal, aremovable brush holder positioning said brushes, and means for adjustingthe transformer relative to the electrodes for varying the tension ofthe brushes.

3. In an electric welding machine the com bination of a welding-throatstructure including two opposed electrodes rotatable about upwardlyextending axes, a transformer directly above said electrodes and havingdepending secondary terminals respectively located above said electrodesand between the axes of the latter, contact brushes interposed between,and making end contact with, respectively a marginal portion of eachelectrode and the under side of the corresponding secondary terminal,and a brush holder removably carried by each said terminal andadjustable relatively thereto to force the upper ends of the brushesinto pressure contact with the underside of the terminal, said brushesbeing demountably carried by the holder and having portions overlyingportions of the holder.

4. In an electric welding machine the combination of a welding-throatstructure including two opposed electrodes rotatable about upwardlyextending axes, a transformer directly above said electrodes and hav-.

ing depending secondary terminals respec-' tively located above saidelectrodes and between the axes of the latter, contact brushesinterposed between, and making end con-' tact with, respectively, amarginal portion of each electrode and the under side of thecorresponding secondary terminal, a brush holder removably carried byeach said terminal and adjustable relatively thereto to force the upperends of the brushes into pressure contact with the underside of theterminal, said brushes being demountably positioned in slots in theholder and having upper-end extensions overlying the holder, and meansfor vertically adjusting the transformer.

5. In an electric welding machine, the combination of a -welding-throatstructure including grooved supporting-roller means andperipherally-grooved opposed electrodes inclined to the horizontal; atransformer above said electrodes having depending secondary terminalswith their lower faces sloped substantially parallel with the upperfaces of the electrodes and between the axes of rotation of the latter,an arcuate brush holder secured to the under side of each said terminal,and an arcuate row of brushes mounted in said holder in inclinedrelation to the plane of the electrode, and making endwise pressurecontact with both the electrode surface near its perimeter and thebottom of the secondary terminal.

6. In an electric welding machine the combination of a base, awelding-throat structure mounted on said base and comprising supportingroller-means and two opposed electrodes rotatable about upwardlyextending axes, a transformer, means carried by said base forpositioning the transformer above said electrodes, means for verticallyadjusting said transformer, said transformer, having secondary terminalsdirectly above, and between the axes of rotation of, said electrodes;and contact brushes interposed between the bottoms of said secondaryterminals and the respective terminal-confronting upper surfaces of theelectrodes and subject to the vertical pressure occasioned bytransformer adjustment, to establish a low resistance electricalconnection between the secondary terminals and the electrodes.

7 In an electrical welding machine, the combination of a main-frametable, a welding-throat structure mounted thereon comprising asupporting roller rotatable on a horizontal axes an opposed rollerelectrodes rotatable about upwardly-extending axes, a sub-frameadjustable longitudinally of the main frame table and carrying saidsupporting roller; two transversely adjustable subframe structuresflanking the first mentioned subframe; slide carriages adjustablymounted in the respective two subframes, means for laterally adjustingsaid respective slide carriages in their subframes, bearings for saidelectrodes carried by said respective slide carriages, a transformermounted above said electrodes and having depending secondar terminalsabove, and between the axes o said electrodes, means v for verticallyadjusting the transformer brush holders carried by the-underside ofadjacent electrodes said terminals, and contact brushes positioned bysaid brush holders and interposed in end-contacting relation betweensaid secondary terminals and the respectively suband-subject to thepressure engendered by vertical adjustment of the transformer.

8. In an electrical welding machine, the

" combination of a main-frame table, a welding said supporting roller;two transversely 1 'two subframes,

adjustable subframe structure's flanking the first mentioned subframe;inclined slide carriages adjustably mounted in the respective means forlaterally adjusting said respective slide carriages in their subfrzames,bearings for said electrodes carried y transformer mounted above saidelectrodes and having depending secondary terminals above, and betweenthe axes of, and parallel with said electrodes, means for verticallyadjusting the transformer, brush holders carried by the underside ofsaid terminals, and contact brushes positioned by said brush holders andinterposed in end-contacting relation between said seconda terminals andthe respectively sub-ad acent electrodes and subject to the pressureengendered 'by vertical adjustment of the transformer.

GUSTAVE v. JOHNSTON.

said -respective'-slidecarriages, a

